M. Brutus to Cicero, written from Dyrrachium in mid-May 43 BC. The Perseus dateline as printed reads Scr. Dyrrachi iii antprid. id. Mai. a. 711 (43); the printed string “iii antprid.” is a corruption of “iii ante prid. id. Mai.” — “the day before the day before the Ides of May,” i.e. 13 May 43. The meta entry’s placeholder of 21 September is far too late and is corrected here. Dyrrachium (modern Durrës) is Brutus’s base in Macedonia while he consolidates his eastern command.

The letter is Brutus’s first congratulation on the victory at Forum Gallorum and Mutina (14 and 21 April 43): his nephew Decimus Brutus’s break-out from Mutina, he says, was both the saviour of Decimus himself and the decisive contribution to the success. The body of the letter is the famous statement of Brutus’s juridical principle. Cicero had written that “the three Antonii” — M. Antonius, his brother L. Antonius the tribune, and his other brother C. Antonius, whom Brutus held captive at Apollonia — are now to be treated as a single case. Brutus refuses. He has not killed C. Antonius, though he could have, because the Senate has not condemned him; he has not stripped him of his property cruelly, nor remitted his confinement dissolutely; and he insists that the question of citizens taken in arms is for the Senate and people to decide, not for a commander in the field. The closing section, broken off in the manuscripts after “when you have set me right * *,” is the first surviving note of the disagreement that will widen through the summer: Brutus’s accusation that Cicero is too quick to trust “a mind once corrupted by lavish gifts” — meaning Octavian — to “bad counsels” will become the central theme of letter 1.17 to Atticus six weeks later.